package com.hmdp.utils;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/*
*主要用来生成全局的唯一id
*
**/
@Component
public class RedisIdWorker {
    /*
    * 开始的时间戳*/
    private static final long BEGIN_TIMETAMP =1699833600L;
    private static final int COUNT_BITS= 32;
    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    public long nextId(String keyPrefix){
        //1:生成当前的时间戳
        LocalDateTime now = LocalDateTime.now();
        long l = now.toEpochSecond(ZoneOffset.UTC);
         long l1 = l - BEGIN_TIMETAMP;
         //2:生成序列号
        //2.1 获取当前日期，精确到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        //2.2 自增长
        Long increment = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);
        //拼接
        return l1<<COUNT_BITS|increment;
    }



}
